Regroover for tires



P 29 194i R. l. VAN ALsTlNE 2,240,382

REGROOVER FOR TIRES Fiied June so, 1939 9.8. 1517. 6. 15'. 5. ...I `;Ir .9. I Inventor,

Z: his attorney,

Patented Apr. 29, 19412 entree STATES PATENT OFFICE 2,240,382 v interimoval. FoRTiREs e yRobert I. Van A lstine, Philadelphia, Pa. e Applicatinmne 30, 1939, serial No. 282,217

(o1. 30g-14o) 9 Claims.

My invention relates groovers for tires. d d

Used rubber tires sometimes become -so worn on the tread that the anti-skidding grooved surface is worn away, either partly or all the way down to the bottom of the grooves, and either over only part of the tread, or the groovingis obliterated altogether. Where there is enough of the tread surface left for safely deepening the grooves, or reproducing the same where they have been worn away, or where the tread surface is built up with an additional layer of rubber, the regrooving is done by the use of a hand tool.

Various kinds of these hand-operated regrooving tools are in use, some more efficient and more easily operated than others. It is VAimportant, in the formation and design of such regrooving tools, that the same be adapted to be readilyV handled without causing undue fatigue tothe operator in the continuous handling of .the tool. The form ofthe handle best adapted for holding the tool in various positions, for ope eration is important, as well as isthe formation of the cutting blade to reduce its frictionas it plows through the rubber surface.'

I have, therefore, various objects in view providing a suitable regrooving tool for tires. Considering the handling of the tool, there are times when the common form ofV drawlknife handles are suitable. These 'handlesfextend'at right angles to the end portions of thlorigitudi# nal body of the tool.` Ina'smuch as suchhandles require a considerable gripping effort to' keep the tool from slipping out of the hands when itis being'pulled to plow Va groove, one of my' objects relates to providing an L-extension to' each of such draw-knife handles. Each extension Vruns part way on to the end portions of the longitudinal body of .the tool, so that these extensions' can lie beneath Ithe fingers of the hand, and can be held with the fingers acting as hooks when pulling the tool, to plow it through the rubber; at the same time, those portions ofthe handles which extend at right angles .to the body 'of the `tool serve, when bearing upon the palm ofthe hand, to prevent the tool from turning in the hand.

In connection with the handles and their L- extensions, I desire to have the same made of heat insulating material, such as wood, and to have these L-extensions releasably fixed, in sliding engagement with the tool body.

Another object of my invention is to have the longitudinal body of the tool, which carries the grooving knife, tubular, so as tok have an' elec# to electrically heated Wretrical heating unit centrally positioned within the tubular body.

A further object is to have the member which is to be used as a knife holding member made of a block of heat absorbing metal, fixed at and surrounding the mid-portion of Ithe tubular body of the tool, where it will also surround the heating unit. v

Another object is to have a portion of the knife holding member serve as an adjustable clamp for the two ends of a U-shaped blade, having the said portion made up of a plurality of separable, heat absorbing plates, bound together by one or more bolts, and having one of said plates extend integrally with the body of the block or knife holding member. My object in using such plates is to adapt the same .to have the sheet metal end or ends of the knife blade gripped between contiguous and releasably bound plates, while at the same time, to build up a heat transferring body portion .to the block, having considerable area of contact between the blade ends and the plates, for transferring heat more readily to the thin blade used.

In connection with the formation of the blade carrying block, I desire Ito have the lower part thereof cut back or tapered, so as to afford the operator a fuller View of the blade, as he uses it. In connection with the formation of the blade itself, one of my objects is to form said blade with blunt extending edges above, and in line with, the cutting edge proper, so that these blunt edges will limit the depth of cut formed by the cutting edge,Y by riding upon the surface of the rubber and not cutting down into it. In providing such blunt surface'riding edges to the blade, above its cutting edge, the knife block can be spaced away from the rubber, and so prevent loss of heat into the rubber and reverse it for the knife.` A Vfurther object in connection with the formation of theblade is to reduce its friction, as' it is plowed through the rubber, by having the same' narrower at the bottom thereof, than atthe topfso tapering the blade, as to its width, that the upper part of the blade will be strengthened by its greater width.

uWith these and "other objects, as will hereinafterappear, my invention resides in certain construction, one` embodiment thereof, including various forms of VVknives, being illustrated in the drawing and being hereinafter described. The operation Vof the same is explained and what I clair'nisset forth. v i

"Figure -1 isan elevation, 'partlyfshown' in section, of a tire regrooving tool embodying my invention.

Figure 2 is an enlarged fragmentary sectional elevation showing the handle and its L-extension for one end of the tool.

Figure 3 is an enlarged sectional elevation of the tool, taken on the line 3-3, of Figure 1, but having the axis of the main part of the handle turned up horizontal and showing the tool knife cutting a groove into aportion of a rubber tire.

Figure 4 is a front elevation of the knife block and knife shown in Figures 1 and 3.

Figure 5 is a side elevation of the form of knife blade shown in Figures 3 and 4.

Figure 6 is a front elevation of the knife blade shown in Figures 3, 4 and 5.

Figures '1 and 8 are side elevations of `modified forms of knife blades, as compared to that shown in Figures 5 and 6, and having the same general,

front elevation appearance as shown in Figure 6.

Figure 9 is an enlarged fragmentary perspective View of a blade, illustrating the Continuity of the blunt surface riding edge with the lower cutting edge.

In the figures- Considering the construction of the tool the body thereof, formed by a long metal tube I5, has its ends I3 and I1 in sliding engagement, respectively, with the tubular bushings I8 and I9. The position of each bushing upon the tube I5 is adjustably fixed by a screw 20, threaded into the bushing. These bushings I8 and I9 enter the respective heads 2| and 22 of the handles 23 and 24, respectively. The long portions of the e.

handles are engaged by -bolts 26, in threaded engagement with the bushings I8 and I9, respectively. E'ach bolt 26 has a head 21, bearing against the shoulder 28, at the upper end of the larger drilled hole 29. Surrounding each of the bushings I8 and lI9 is a wooden sleeve 3U, which, f

with the bushing it covers, forms an L-extension to eachl of the handles 23 and 24.

Centrally positioned within thef'tube I5, up against the cross-screw 3|, is an electric heating unit 32. I into the head 22 of the handle 24, and thence through the tubular insulators 34 and 35, to connect with the unit 32. The conduit 33 hasl a plug 36, adapted to go into the usual outlet socket for current, to heat the unit 32.

Positioned upon the 'tube I5, and adjustably fixed thereon by screws 31 and 3B, is the metal knife block 39, which surrounds the tube I5. This mounting of the cutter block 39 makesV it possible to shift the block along the tubular member I5, as desired by the user, and to rotate it around the tube to vary the angular relationship between the cutter and the handles 23 and 24. This block 39 has a narrow or plate-like extension 46 integral therewith. Adjoining this plate extension 49 are other plates 4I, similarly shaped to the extension 4U, and preferably in contact with the tube I5 for the transfer of heat thereto from said heating unit 32. Passing through each plate 4 I, and theplate extension 49, are two bolts 42 and 43, having heads 44fand nutsl 45. VUnder the heads 44, next to an outer plate of theplates 4I, is a short flat bindinglink 45. The boit 42 is preferably positioned nearer toy the tube I5 than is thebelt 43 for positioning. the sheet metal, U-,shaped blade 41, as `shown in Figurel 3, The blade 41 has two leg portions 4 3 and 49,. and a bent portion 55. Each leg porticnis notchedv at 5l, forming tWQnaIrGyr ends. 5.2 and- Infie- Wires from an electric `conduit 33" pass ures 1, 3 and 4 the ends 52 of the leg portions 48 and 49 are positioned between adjoining plates of the plates 4I and pass up between the bolts 42 and 43, and are there clamped by the said bolts. The bent portion 59 of the blade 41 has a forward cutting edge 54, and a rear cutting edge 55. The upper part of the cutting edge 54 merges on each side into a blunt, non-cutting edge 56, and the upper part of the cutting edge 55 merges on each side into a blunt, non-cutting edge 51. These blunt edges 55 and V51 are adapted to ride upon the surface of the rubber to limit the depth of cut in forming a groove in the tire tread, and are adapted by being spaced from the plates' 4I to keep the heated block 39 from touching the tire surface. t will be noticed that the block exten sion 40, and its adjoining plates 4I, are formed with a rearwardly inclined front part 58, so as to afford the operator a full View of the blade, or that part thereof which extends up from the tire tread, as the operator progresses with'the forma'- tion of the tire grooving.

The sheet metal L J-shaped blades 59 and 65, shown respectively in Figures' '1 and 8, each has a forward extension 6I. Each ofthe extensions 6I has its under edge 62- made blunt, to be non-cutting. Extending below the edges 52 is the rearwardly inclined cutting edge 53, which is shown more inclined in Figure '1 than in Figure 8. Each of the blades 59 and 6U has lip-standing extensions 34 adapted to be clamped between the plates 4I and between the boltsv 4,2 and 43.

The enlarged view of a portion of a blade, such as is shown in Figures 7 andrS, is more clearly shown in Figure 9 to Vbe rounded at the blunt edge 62, and the sharpness of the cutting edge 53 is better illustrated.

While the cutter blades, adjacent their cutting edges, are relatively narrow, as at 59, Fig. 5, and at 53, Figs. '1 and 8, so' that they will pass easily through the rubber, they are made wider above the eutting edges to give the blades added strength and rigidity.

For operation, the operator first selectsV the style of blade which he thinks most suitable for width and depth of groove to be cut. rHe next holds this bladewith itsv lip-standing legs parallel and inserts thern between such adjoining plates, or pairs of` plates, asl will4 approximately hold the said legs parallel when clamped by the bolts 42 and 4 3. The. plates 4.I Vary in thiekness, so as to facilitate suchjselection as will enable theoperator to have the blade legs clamped parallel.VV In selecting a blade that isV best s uited f orj his purpose, the operator also has al choice. of one of two cutting edges Shown in the blade. 4,1, of Figure 3, wherein thev blunt, edge 5.6, being farther from the lower part of the'adjoining edge than the blunt edge 51, will permit the blade 41 to cut a deeper groove. The blunt surface runningedges of suchbladesreadilyV limit the depth of cut, when frming the grooves and, at the same time, keep the heated clamping block and its plate, parts from coming in contact with the rubber,I so the blade can thenv be continuously supplied more readily with heat.

Having the tool equipped with the desired blade, thev operator next plugs intov a nearby socket for .current to heat the device and proceeds to do his grooving. In Figure 3, the forward cutting edge 56 of the. blade 41 is shown in the. act of plowing into the rubber tread to form a groove 51. Sli-is the out out portion. of rubber` asit leaves the lenire Themen? forward. @eier-@Cline edge 56 of the blade 41,.A is shawn` riding upon the upper surface of the tread (it and limits the depth to which the blade can go into the rubber. The lower rounded part of the blade is slightly tilted by the way the operator holds the handles of the tool. This tilting causes the blade to pull down into the rubber until its incutting is limited by the blunt non-cutting riding edges of the blade.

In handling the tool, the L-extensions Sii of the handles enable the operator to have the long portions of the handles lie longitudinally against the palms of his hands, while his fingers are bent forward over the L-extensions as hooks, to give him a much better hold on the tool in pulling its knife through long circumferential grooves or cross grooves; but, if desired, he can hold the tool by gripping the handle parts in the usual way.

Ina-smuch as changes can be made in the construction of the tool or its blades diifering from those illustrated and described, without departing from the spirit and scope of my invention, I wish to include all modifications which come within the scope of the following claims.

I claim:

1. In a tire grooving tool a U-shaped blade formed with a cutting edge at its lower curved portion, said blade having blunt forwardly extending edges adjoining the upper ends of said cutting edge, said blunt edges being adapted to ride upon the surface of the rubber tread of a tire to limit the depth of cutting by said cutting edge.

2. In a tire grooving tool a U-shaped blade formed with a cutting edge at its lower curved portion, said blade having blunt, forwardly extending edges,I adjoining the upper ends of said cutting edge, said blunt edges being adapted to ride upon the surface of the rubber tread of a tire to limit the depth of cutting by said cutting edge, said cutting edge being inclined rearwardly.

3. A tire grooving tool including a tubular member, a handle xed to each end of said member, electrical heating means positioned within said tubular member, approximately inidway of its ends, an electrical circuit means connected with said heating means, adapted to be connected with a source of electricity, a grooving knife, a heat absorbing block positioned upon the outside of said tubular member in a transverse plane to the same, which passes through said heating means, a clamp on said block adapt-` ed to releasably hold said knife, said clamp ccm-` prising a plurality of heat absorbing leaves adapted to have a. part of said knife held between two of said leaves that are contiguous, and a binder for compressing said leaves together to hold said knife, one of said leaves being integral with said block.

4. In a tire grooving tool, a U-shaped blade the sides thereof being relatively narrow adjacent the lower curved cutting portion of the blade,

the cutting edges of the blade extending upwardly and forwardly to form portions of greater width above the lower curved portion of the blade, the said upwardly and forwardly extending cutting ed es merging into blunt non-cutting forward extensions adapted to ride upon the surface of the tire to limit the depth of the groove.

5. A tire grooving tool comprising a tubular member, a heater therein, handles one at each end thereof, a heat transmitting block mounted on the tubular member to be hea-ted by the heater, a cutter mounted on the heat transmitting block, and means for holding the cutter in position on the block.

6. A tire grooving tool comprising a tubular member, an electric heater therein, handles one at each end thereof, a heat transmitting block rotatably mounted on the tubular member so as to be heated .by the heater, means for holding the heat transmitting block in position on the tubular member, a cutted mounted on the heat transmitting block, and means for holding the cutter in position on the block.

7. A tire grooving tool comprising a cylindrical tubular member, heat insulating L-shaped handles one for each end of the tubular member one leg of each handle enveloping one end of the member and the other leg of each handle projecting from the rst mentioned leg at an angle thereto, so that the hands of the operator may engage with either or both legs of the handles, an electric heater within the tubular member between the handles, a heat transmitting block adjacent the heater to be heated thereby, a cutter ou the block, and means for holding the cutter in position on the block.

8. A tire grooving tool comprising a cylindrical tubular member, heat insulating L-shaped handles one for each end of the tubular member one leg of each handle enveloping one end of the member and the other leg of each handle projecting from the first mentioned leg at an angle thereto, so that the hands of the operator may engage with either or both legs of the handles, an electric heater within the tubular member between the handies, a heat 4transmitting block rotatably mounted on the tubular member, a cutter on the block, and means for holding the cutter in position on the block.

transmitting block surrounding the tubular member in heat conducting contact therewith and adjustable longitudinally and angularly with respect thereto, a cutting blade on the heat transmitting block, and means for securing the cutting blade in position on the block.

ROBERT I. VAN ALSTINE 

